We live in a country of 350 million people. At any given time, around 1.2 million people serve in the military, or about a third of a percent of the general population. Of that third of a percent, the "tooth to tail" ratio is 8:1 (150k), but "tooth" is combat arms which includes artillery, tankers, cav, engineers etc. Even within the Infantry there are mortarmen, mechanized, anti-tank squads etc. It's hard to say for certain, but the number of dudes in the military whose job it is to kick the doors and shoot the faces is likely no more than 50k at a given time. Of that, only a minority will deploy and a minority of those see combat. In the twenty years of war in Iraq and Afghanistan, the military has awarded right about 77k CIBs and 47k Purple Hearts out of 2-3 million total deployed over that time. Obviously, there is some overlap between those awards.
For the uninitiated, the Combat Infantryman Badge is intended to identify those members of the infantry who have actually "close(d) with and destroy the enemy with direct fires.", and the PH is known colloquially as the Enemy Marksmanship Badge. But there are some caveats. For reasons I will explain, the numbers we pull from awards like this are likely a high-end estimate, rather than a minimum, but counting the Marine 0300s and whoever all else could push the numbers up a bit.
The CIB is awarded at the company level, and only in the Army. This means if one dude in an infantry company (~100 men) gets in a firefight, the whole company gets their CIB. Much of the fighting these days is very small unit engagements, so it is quite common for only a few squads or teams in a CIB company to have actually seen the combat. OTOH, more people than infantry get into shooting scrapes, I know a couple cooks with multiple engagements just because they used to volunteer to fill out patrols that were short on people. Given the nature of the conflict, a lot of people who weren't infantry, or even combat arms have seen combat. However, if they do, it's usually because of bad luck or the military ran out of infantry to do that job. It's impossible to say definitively given the data available to me at the moment, but I very much doubt the total number exceeds the number of infantrymen with CIBs. Lots of cav guys saw action as route security, lots of random MOS people got blown up en route or pressed into some role they weren't trained for. But the guys who do the job day in and day out of locating, fixing and killing the enemy is a rather select group.
So too the Purple Heart has gone to a lot of people who don't do that sort of job. Mortars dropped into a FOB can hit anyone, and roadside IEDs don't care if you're on the road to take water to an outpost or heading out on a raid. But they are more common among the people who are in the most dangerous situations more regularly.
Let's bring it all those numbers and assumptions together for a moment, because I'm describing a group of people who are very, very abnormal, and very far out on the distribution tail of the violence bell curve. Let's round up to make the math easy and account for POGs and Marines and call it a hundred thousand men over twenty years (and yes, to the closest approximation, it is all men). It's three ten thousandths of one percent of the general population. That's the high estimate, the real number could be significantly lower still. And the number who deploy multiple times is much, much lower.
When American foreign policy decides some poor dirt farmers on the other side of the globe need some freedom in their lives, maybe one ten thousandth of one percent of the population is who gets sent to do the actual violence of empire. I am one of those men. I have a CIB and a purple heart. Within the rarified community of professional actual soldiers, I am a small fish in a tiny pond. I was not special forces (or, technically I was briefly, but not really). I was a reasonably high-speed infantryman with a penchant for guns who worked himself into a sniper platoon in a fairly trash unit. I made sergeant, ate an IED and got med-boarded out of the military. A short, somewhat spicy but relatively unremarkable military career for an infantryman.
Much of what the general public hears about combat, even "first hand accounts" is not from people who actually do this job. As I have hopefully established, this is a very small, very highly selected and very abnormal group of people. Most of what you read ore hear in war accounts is from the middle classes, which in the military means officers. Officers are not soldiers. They are managers of soldiers. During conscription, it was at least possible for a southern gentleman of letters like Eugene Sledge or a Junker scion like Junger to write an account of actual enlisted combat, if unlikely. In today's volunteer military, this is almost never the case. The venn diagram of actual front-line soldiers and people who can write competently in an educated manner for general consumption is essentially two separate circles. These are not generally guys with college degrees, because if they had one they'd be an officer. There are exceptions, but we'll perhaps get into that at another time.
This hopefully will go some way to explaining my arrogance in writing about the topic. IQ and violent tendencies tend to be negatively correlated, and I am way out on the right tail of of the distribution on both. If that seems self-aggrandizing, rest assured that neither has done me any good.
So who are these men? Who carries the torch of empire into the barbarian wastes of the Korangel? Who sits behind the machine gun of a HMMWV? Who donkey-kicks the doors off their hinges and plunges into the black interior following the blinding light of his Surefire? Who sits in a ditch for three days waiting to shoot a retarded teenager whose dad got paid $200 to have him drop an IED in a pothole?
In short, they're degens. Poor and working class kids, half of which aren't old enough to buy beer. Mostly rural whites and hispanics. Roughly a quarter are from Texas alone. The South more generally provides well over half, maybe two thirds of the total. Most of the rest are from the Midwest and West. They self select. These are guys who asked to be in the Infantry, and survived the training and indoc. Nobody winds up on the pointy end of the spear by accident. It's the worst job in the military, so the people who volunteer for it are driven by very different considerations to most. It's also the highest status within the violence hierarchy.
It's a weird group. There's a lot of immigrants, not all of them hispanic. A surprising number of professional soldiers from other countries come to the US just for the action. If you're just itching for a fight but are born somewhere too peaceful, coming to the US will greatly increase your likelihood of getting into the shit. I've met British Marines, African princes, a German seminarian who dropped out to join the US infantry. There's some tiny minority communities that are heavily overrepresented though still small in total numbers, like Native Americans, the Samoans, the Hmong and the Sikhs. East asians are rare, and black Americans, while overrepresented in the military generally, are underrepresented in this part but still common.
We are united by a few characteristics, most generally the privileging of suffering as a badge of honor, physical violence, and a death wish. One does not join the Infantry to live a quiet life to a ripe old age. Mostly, I think we want to fuck around and find out. Like the movie says, how much can you know about yourself if you've never been in a fight? I had a lot of reasons for joining up, but I think the most basic was a desire to test myself and find out if I had what it took to face another man in mortal combat. To "see the elephant", or any of the other thousand euphemisms we use for fighting and killing our fellow men. To take the ultimate risk.
A recruit can get all the benefits of military service in a safer and more sustainable career. The infantry chews up men, minds and bodies, training alone eliminates hundreds of thousands. A twenty-five year old infantryman is probably middle management, a thirty-year old is probably out of the field as a platoon sergeant. The incessant road marching ruins feet, ankles and knees. The heavy packs wreck spines and shoulders. The heat, cold, wet and sleep deprivation cull the sensitive and the civilized. The social aggression removes the timid and the hazing removes the bitches.
There's an old glib saying that captures the esprit of the group. "The cowards never started and the weak quit along the way. That just leaves us.".
As a composite character, I give you the US infantryman. He is nineteen or twenty years old, grew up in a trailer park, has a kid or two with women he's not married to, is married to a woman with kids that are not his. He'll be divorced in a year. His family are construction workers, nurses, truck drivers, retail workers, garbage collectors, heavy machine operators, drug dealers, petty criminals, major criminals. He is dumber than average, hated school, has never read a book not assigned in class. He's been in jail multiple times, and probably will be again, mostly for low level stuff like underage drinking, vandalism and fighting. He binge drinks and smokes when in garrison, dips in the field. He gets in fistfights on a regular but extended basis with members of his own unit, in group conflict with other units, or with civilians on liberty. His politics, if he has any, are somewhere to the right of Genghis Khan. He drives a pickup truck, a Mustang, or a heavily riced-out import and is dead broke most of the time. He is, in short, perilously close to the underclass of our society, and there's a lot of crossover. His life is boredom, fear, pain and the brotherhood of those who live in fear and pain. His values are foreign, rude and frightening to those not of his group.
He is the world elite of the violent class. The modern equivalent of a knight, loaded down with many years' wages' worth of technology, weapons and armor. Far better trained, supplied and equipped than his adversaries. The big stick that the world hegemon swings in the anarchic world of international politics. The very tip of the spear. The point of empire.
In our modern peaceful society, that point has become very fine indeed.